The U.S. Geological Survey's (USGS) National Water Information
System (NWIS) is a comprehensive and distributed application
that supports the acquisition, processing, and long-term
storage of water data. USGS Water Data for the Nation Site serves as the publicly
available portal to a geographically seamless set of much of
the water data maintained within NWIS
(additional background).

USGS Water Data for the Nation Site provides access to water data from over 1.5
million sites in all 50 States and additional border and
territorial sites. The data are organized within the
categories listed to the left.

The water data available via this site have been acquired as
part of the USGS investigations of the occurrence, quantity,
quality, distribution, and movement of the surface and
underground waters that constitute the Nation's water
resources. Additional information about the USGS and water
resources of the Nation is available at
water.usgs.gov.